NoMethodError in Ruby with Comparison Statement

Question

I decided to start learning a bit of Ruby and went to attempt an insertion sort version in Ruby (2.3.0). However when my program checks to see the position and whether to swap values it returns a NoMethodError for '>'. More specifically:

./rubyInsertSort.rb:28:in `block in sort': undefined method `>' for 1..4:Range (NoMethodError)
from ./rubyInsertSort.rb:26:in `each'
from ./rubyInsertSort.rb:26:in `sort'
from ./rubyInsertSort.rb:22:in `main'
from ./rubyInsertSort.rb:40:in `<main>'

Here is the code for the sorting method:

def sort(input, valueAmount)
  for i in 1..valueAmount
    j = i
    while j > 0 and input[j - 1] > input[j]
      input[j], input[j - 1] = input[j - 1], input[j]
      j += -1           
    end
  end

  #Output loop
  for i in 1..valueAmount
    puts "Sort Value #{i} = #{input[i]}"    #Outputs the sorted array to the console
  end
end

I know this is probably something trivial and really simple but I can't find a question on here or elsewhere with a solution and any help would be appreciated!

Answer 1

Modified your version

def sort(input, valueAmount)
  for i in 1...valueAmount  # Added a dot
    j = i
    while j >= 0 and input[j - 1] > input[j]  # >= instead of >
      input[j], input[j - 1] = input[j - 1], input[j]
      j += -1
    end
  end

  #Output loop
  for i in 0...valueAmount  # Added a dot
    puts "Sort Value #{i} = #{input[i]}"    #Outputs the sorted array to the console
  end
end

And here is my version (without output)

def insertion_sort!(ary)
  return ary if ary.size < 2
  1.upto(ary.size - 1) do |i|
    i.downto(0) do |j|
      break if ary[j - 1] <= ary[j]
      ary[j - 1], ary[j] = ary[j], ary[j - 1]
    end
  end
  ary
end